MOHAMED, SALEH M. Molecular Biology Dept., National Research Centre, Tahrir St. Dokki, Cairo, Egypt. - Endoproteases in Sorghum bicolor (Cv. Giza 10) during germination.
The pattern of endoproteolytic activities following Sorghum
bicolor (cv. Giza 10) grain germination was studied. The maximum
activity of acidic, neutral and basic of sorghum endoproteases was
observed on days 6, 4 and 8 of germination, respectively. The effect
of class-specific inhibitors on the endoproteolytic activities during
grain germination, assyed in solution with azocasein as a substrate,
indicated that: a) Metalloendoproteases were detected from day 6 to
day 10 of germination, using ethylenediaminetetraacetic acid (EDTA)as
an inhibitor, b) Aspartic endoproteases were detected from day 10 to
day 14 of germination, using pepstatin A as an inhibitor, c) Serine
endoproteases were detected at all stages ofgermination, using
phenylmethyl sulphonyl fluoride (PMSF) as an inhibitor, d) Tiol
endoproteases were detected from day 2 to day 6 of germination, using
iodoacetate (IA) and p-Hydroxymercuribenzoate (p-HMB) as inhibitors.
The effect of class-specific protease inhibitors was also tested on
endoprotease assays in electrophoretic gel. The endoproteolytic bands
of Sorghum bicolor grain germination were arbitrarily clasified
into three groups A, B and C contained less or more than 8 bamds.
Group B and, to a lesser extent, group C are contained metallo, serine
and thiol endoproteases. this work shows that germinating Sorghum
bicolor contains a complex set of endoproteases could be
potentially a good starting material for preparation of different
classes of endoproteases.
Key words: endoproteases, inhibitors, Sorghum bicolor